Incontinence, i.e., uncontrolled release of urine from the bladder, has been noticed as a condition affecting a growing segment of the female population in the United States. It is believed that, in the U.S., approximately 40% of community-dwelling females over 60 years of age suffer from urinary incontinence that is felt to be socially disabling.
See J. Urol., vol. 136, p. 1022, 1986. This also has a huge economic impact on society. A recent estimate of the annual direct costs of caring for persons of all ages with incontinence is about $11.2 billion in the community and about $5.2 billion in nursing homes (based on 1994 dollars). See Geriatric Nephrol. Urol., v. 4, pp.85-91, 1994.
The problems of incontinence in females can be broadly grouped into one of two categories. The first category is one where the incontinence is due to involuntary contraction of the bladder (or detrusor) muscle. Such a condition is sometimes termed "an unstable bladder." The second category is the more common one and comprises stress-induced incontinence, which is best understood as involuntary loss of urine occurring in correspondence with an increase in the female's abdominal pressure, e.g., during a sudden bout of coughing.
Over one hundred surgical/operational procedures, aimed at controlling or obstructing urine flow through the female urethra, have been proposed to alleviate this common problem. The fact that there are so many different surgical procedures proposed is evidence that no single operation has been successful in correcting this condition.
Several devices offering alternatives to surgery are commercially available to provide temporary relief from the problem of female incontinence. These include, for example, the "Artificial Urinary Sphincter", marketed by American Medical Systems; the "Reliance" (intra-urethral plug) and the "Impress" (external urethral patch), both marketed by Uromed; and the "Capture" (also an external urethral patch) marketed by Bard Urologic.
The "Artificial Urinary Sphincter" comprises an inflatable cuff, which is a surgically implanted device which encircles the user's urethra. The cuff is manually deflatable by actuation of a finger-actuated pump placed in the user's labia majora. There are, however, certain limitations in the use of such a device. For example, the cuff is relatively large and cumbersome to install surgically as it requires dissection around the proximal urethra to allow placement of the cuff between the posterior urethra and the anterior vaginal wall. Furthermore, the pump and release mechanism often cannot be comfortably placed in the user's labia majora. During use, this device requires the user's urethra to be continuously obstructed via the inflated cuff and has to be manually released by compressing the pump when voiding is desired. Such devices also have significant technical failure rates. See J. Urol., vol. 136, p.778, 1987. For these reasons, the artificial splincter is rarely implanted in female patients with stress incontinence.
The "Reliance" device is an internal urethra plug which must be inserted by the user into her urethra. Following the insertion, the user employs a syringe to inflate a small balloon at the distal portion of the device which rests at the neck of the user's bladder to thereby obstruct urine flow. When the user needs to void she has to pull on a string at the level of the external urethral meatus which deflates the balloon and permits the user to withdraw the device. A major drawback of such a device is that it is designed to be used as a disposable single-use product. The typical user thus requires numerous devices every day and incurs significant expense. In addition, the device is a temporarily placed, and frequently replaced, foreign body located in a highly sensitive region of the urethra and this may pre-dispose her to urinary tract infections and urethral irritation.
The "Impress" is an external patch which is placed over the opening of the urethra by the user and is held in place by an adhesive. When the user wishes to empty her bladder, she must remove the patch and must replace it with a new patch after voiding. One of the major drawbacks of such a device is leakage of urine around the patch because of insufficient adhesion. In addition, it also has the limitation of being a single-use disposable product, which requires the user to carry a number of the devices with her and incurs significant expense.
The "Capture" is another external device, which is also placed over the opening of the urethra. This device is marketed by Bard Urologic and is somewhat similar to the "Impress" device but remains in place via a suction created during placement of the device. The limitations of such a device include ineffective fixation on to the external urethra, cost, and inconvenience due to it's being a single-use disposable product.
As previously mentioned, over a hundred surgical operations have been described to correct female stress incontinence. These operations are aimed at elevating and/or stabilizing the urethrovesical junction or partially obstructing the urethra. Since so many operations have been described, obviously no single operation has been successful in completely eradicating this condition. The difficulty revolves around the fact that there is no standard technique for determining the amount of tension to be placed on sutures or sling material. Also, significant complication rates have been reported. See "Clinical Practice Guidelines for Urinary Incontinence in Adults: Acute, and Chronic Management", No. 2, 1996 Update, pp. 53-59, published by the U.S. Dept. of Health and Human Services, Agency for Health Care Policy and Research.
Accordingly, there is a present and significant need for a device and a method of providing protection against the inconvenience of stress-induced incontinence which would be automatically actuated only when the female user experiences a rise in abdominal pressure, of sufficient magnitude to produce leakage.